This application is to develop the PEPD technology to survey the mutation status of hundreds of DMA markers in a vast excess of wild-type DNA for cancer screening. Specifically, we will develop a fecal DMA testing assay for colorectal cancer (CRC) screening. Fecal DNA testing is emerging as a novel method for CRC screening. However, fecal DNA testing is a technical challenge, as no single marker can indicate all CRCs and thus a large panel of markers must be utilized to increase sensitivity. As a result, existing fecal DNA methods are not suitable for screening because of either poor sensitivity or high-cost. In Phase I, we demonstrated that a novel technology called PEPD could survey a number of mutations in a 10,000 folds more excess of normal DNA by a single assay, making it possible to detect mutations in a sensitive and cost effective manner. To the best of our knowledge, this provides the first demonstration of surveying the status of a large number of DNA markers with such high sensitivity by a single assay. The PEPD method is simple, but very powerful and thus it can be a universal mutation detection technology platform. Hence, success of this project will have a profound impact on mutation analysis and thus cancer screening. The PEPD-based assay developed in Phase II can detect 80-85% of CRCs in a cost-effective manner. Success of this work is of great significance in CRC screening, as it can transform fecal DNA testing. Eventually, it allows physicians to detect the majority of CRC simply by taking a piece of stool for DNA analysis to save thousands of life each year from CRC. In addition, this assay can be used to monitor CRC patients and risk assessment after treatment. [unreadable] [unreadable] [unreadable] [unreadable]